Motor lubrication



May l, 1951 G. E. BuRKs x-:T AL.

MOTOR LUBRICATION 2 Sheets-Sheei l Filed June 4, 1945 ldllm S. /s n wf/9m m eir A @am am w Patented May 1, 1951 Y 2,550,967 M910?? PUBEIQAFION George E. Burks, Peoria, and Ronald R. Robinson,

" Mortonftlllf, as'signors to iCaterpillar'lTractor Coaf'San Leandro, Calif., a corporation of ...Cali- Application gunefi, 1945, Serial No. 597,52@`

The present invention relates tomotor lubrication Farid' particularlyto" a"`1ubric"ating" system for 'internal combustionA engines` and the like.

vIrrnost internal combustion engines', lubrication offbearings' other moving parts is accomplished by providing a supply of lubricantin ar'e'sifvoir fhs'ii'chasnthe crankc'aseof the engine and"T A'pumpingr liiloricant'ffrom'A this reservoir throughsuitable conduits' to thparts" to be lubricated." Vrlhelubricantdrains back to the crankcaser from`fthevario1s"points'at which it'isdisenrgedfand is thii'seonstntiy circulated to the bearing surfaces "lcy' tl1e"pump; Itv Vis "common practice tof employ "a psitive4 displacement type pump for circula-ting lubricant' and to drive the pump 'by connection Withrotatin'g parts of the engine' such; for example, as the'camshaft. As al vresult of this practice, the speed .of the pump is'de'ter'mined bythe speed ofthe' Avengine and the supply of lubricantto the bearings'i's not uniform butfvar'i'es" greatly v'vith enginespeeds. At high speedsthe engine-operates thepump' at capacities farf'n "excess" 'of thelubr'ieation requirements of the bearings'. This isunde'sirable b'case'itre'- sults'inagitation and churning of thelubrica'nt to'thefe'xte'nt' that it becomes fdoamy and includes aconsider'able'quantity'of air in emlsion which greatly"increases` itsbulk and'reduces'its elli# ciencyvas a" lubricant.

r`rSome attemptshave been made to relieve the pressure"andagitation of' lubricating 'oil' in `sys'. tems'of this' kind' and such attempts include the provision o i a"pressure'relief"valve` in the'system Offdistriblltirig conduits at thle'discharge Side of the"pumpi' r'This hasl the advantage ofreducing the pressure inthe distributingconduits and at the bearings but it does notovercome' thei'pririciparcausecf agitation of the "oiifwlhich is the 4"Itis anobject ofthe' present invention to overcoin'ey the above described" disadvantages 'in motoiflubricationiandto prow/'idea jinthod f d istributig l"'l'ubricarit and alubrica'tingf system Wh'ere'in'sa 4predetermined maz'cimum of lubricant is directed` to "bearings "and "other 'parts to be lubricatedand wherein no'morethan a necessary quantity ofilubricant is directed through' 0r' slibn jectedtc thechurning and agitatingaction of ,the lubricant pump;` Another 'obje'ct ofi allein-v ventionl isv the provision offa motor lubricating system' having ap'ump driven by motor operaP tion butiincludng Vmeans 'to' limit the "cuantity ollessH of its speed' of voperation and in' acl @marne with the-requirementsofthe bearings'A bricantsliopled tothe intake of thepiimp.

fiolai'ms. (o1. 18er-'6) to be lubricated. A still further object of the invention is" the provision 'of a motor lubricating system han/'ingv means to limit the `delivery "o'f the lubricant' to 'bearing' surfaces under ordinary 6p"- erating' conditions'and othen'means'to insure adequate lubricationf the'bearings upon starti-V ing of' the motr'when the lbric'ant is coldand therefore unusually Viscous and diilicult to ciricula.. e, Further and more specic objects and advantages of the invention "are made vapparent vin the following speciiication""wherein' reference ifs made to' the accompanying drawings. In the drawings:

Fig. 'l `isa diagrammatic View of a motor lubricating systemembodying the principles of the present invention; and 'i Fig. 2 is a vertical sectional View through a lubricating pumps'uch as lmay housedy in tl'le` system shown' in Figfl and also illustratinga modified type of a control valvel shdvvfrin Fig. l.

While there are many parts ilr'an internal combustion engine which mstbe suppliedfwith lubricant, the mainbearings ofthe crankshaft are generally considered the most critical and the present invention is therefore 'illu'strated and described in connection with the spply of lubri-`A cant to such bearings though vit"vvi1l` be under-v stood as the description proceeds that these' bearings are talen'as typical for purposes of illustra-v tion. i

In Fig. 1 of the drawings the crankshaft of an' internal combustion eng'n is 'indicated atv I Il as having the usual fly wheel I I and as having conventional ranksh'aft" bearings indicated 'at l2, I3 andlll. The'pa, or bottom of thecrankcase housing, is diagrammatically"illustrated at l5 and 'isshownas having a depression' Vor sump IAB which serves toretain a supply" of oil to beidelivered to the bearings of the engine such as those typified at I2, I3 and I4. A pump I1 is connect-V ed with and'driven'by a rotating" shaft I8 vvhic'h may' be the camshaft@ any oth-@fronting pain of theengine'frorn Which'a'pump drivemay conf veniently be' taken. "The"puinp Il Vwithdraws Voil from 'the sump I Eithrough a cnventional'strainer I9 andthrough intakpipesl) and' ZI'andfdscharges the same througha discharge 'pip e"22 which"communicateswith `a m'an'ifdid '23. Branch pipes 2li, "25 'and 26 communicate' between themaiifoid'zs and the nearingsflz; la anali, respectively', vand in" a" 'conventional' manner that oil Withdaw fro"`t1e 'Slml 'GWSMon-lstantly 'supplied'tb th`bearin'g'suface`s in 'd of'lubricationf' Excessoilvfroitl'ie bearingfsdi' y back into the crankcase I5 and is returned to the sump I6. In the event that any substantial quantity of oil collects at either end of the crankcase, as might be occasioned by tilting of the engine as where a vehicle driven by the engine is traveling up or down hill, auxiliary or scavenging pumps may be employed to return such accumulation of oil to the sump. Such pumps are illustrated for example at 28 and 29 as also being driven by the camshaft I8. The pump 28 is arranged to withdraw oil from one end of the crankcase through a filter 30 and an intake pipe 3l and to direct such oil through a discharge pipe 32 which leads into the sump I6. 'I'he pump 29 has a corresponding filter 33, intake line 34 and discharge line 35.

It is undesirable to deliver oil to the bearings I2, I3 and I4 and to other bearing surfaces at excessive pressures because the presence of high pressure in such a system requires unnecessarily strong tubing and connections to prevent bursting and also because the circulation of large quantities of oil through a pump and distributing system results in undesirable agitation and foaming of the oil. In order to prevent excessive pressures in the distributing system, pressure relief valves have heretofore been employed on the discharge side of the main pump Il. Such valves are somewhat in the nature of that shown at 36 in Fig. 1 wherein a spring loaded check valve is shown as communicating with the discharge line 22 through a pipe 3l and having a return line 3B for by-passing the relieved oil to the sump I6. Such a valve was previously relied upon as the only means for controlling the pressure in the distributing system and the pump in such cases always delivered its full capacity depending upon the speed of operation of the motor. Consequently, when the motor was operated at high speeds, the pump was handling several times the actual volume and pressure of oil required at the surfaces to be lubricated with the excess volume and pressure being relieved through a valve like that shown at 36.

In the present invention, the valve 36 is used only as a safety device to relieve pressure in the distributing system in the event of failure of some other part. The quantity of oil delivered by the pump I1 to the bearing surfaces is constantly regulated by a pressure actuated control valve shown at 40 dispo-sed on the intake side of the pump I1 and connected between the conduits 26 and 2i. The valve 46 regulates the amount of oil flowing to the pump I'l from the sump I6 and is operated in response to pressure of oil in the distributing system and preferably at a point adjacent the bearing surfaces. For example, the valve 4I] is shown as a cylindrical housing with a reciprocal plunger 4I having a tapered end 42 cooperating with a valve orifice which is defined by an annular insert 43. A spring 44 normally urges the plunger 4I toward its full open position where the small end of the taper 42 cooperates with the control orifice to permit a relatively large flow of oil through the intake side of the pump IT. A conduit 45 communicateswith the valve housing 40 to com= municate pressure to the plunger 4I therein in opposition to the pressure of the spring 44. This conduit leads to a point in the distributing system adjacent the bearing surfaces to which oil is being supplied as shown, for example, in the drawing where the conduit 45 communicates with the branch pipe 25 leading to one of the main crankshaft bearings. Consequently, the

pressure in the distributing system adjacent the points to which lubrication is being supplied is transmitted to the valve housing 4!) and opposes the action of the spring 44 in positioning the plunger 4I to control the supply of lubricant to the pump I1. The pump is therefore permitted to pick up and direct to the surfaces to be lubricated only the quantity of oil necessary to supply the required volume and pressure at said surfaces, even though it may be operated at high speeds which would normally effect pumping and agitation of several times the required quantity of oil. In the event of any failure of the valve 4U to restrict the ow of oil to the intake side of the pump, the valve 36 will function to relieve accidental excessive pressure in the distributing conduits.

Under some conditions of engine operation such, for example, as starting in cold weather when the lubricant in the engine becomes viscous and diicult to circulate, it is desirable to direct a greater than normal supply of lubricant into the distributing system. To accomplish this a modified form of valve 43 may be employed and such modification is illustrated in Fig. 2 wherein the pump I1, filter I9 and valve 43 are illustrated in a typical practical arrangement. In this View the pump is shown with conventional gear type pumping members 5U and 5I and with an intake passage 52 and a discharge passage 53 with which is associated the spring loaded pressure relief valve 36 described in connection with Fig. 1. The filter i9 is shown as a housing with an inlet 54 in its bottom and is directly connected with the intake portion of the pump housing. The filter may contain any suitable type of oil filtering unit conventionally used for this purpose. The valve housing 40 is shown as formed integrally with the intake passage of the pump and contains the plunger 4I with a tapered end 42 registering with the control orifice insert 43 and biased by spring 44, all operating in the manner described in connection with the valve and corresponding parts illustrated in Fig. 1 In this modification, however, the conduit 45 which communicates with the distributing system to transmit pressure to the plunger 4I in opposition to the pressure exerted by the spring 44 is connected with the side of the housing 40, rather than to its end. rIhis connection is made by an adapter 56 secured in place by a threaded screw 57 which is centrally bored as at 58 and radially bored as at 59 to communicate oil pressure to the side of the plunger 4I. Adjacent the end at which liquid pressure is applied the plunger 4I is slightly reduced in diameter as indicated at t6 and its face at the same end seats against a shoulder 6l which prevents pressure entering through the conduit 45 and tting 5l from being exerted against the plunger in opposition to the spring 44. Consequently, upon cold starting of an engine when the oil is highly viscous the pressure directed to the side walls of the plunger 4I at its reduced diameter 66 will not effect its movement in opposition to the spring 44 and the pump will receive and deliver to the distributing system its full capacity of oil, the pressure being relieved only by the relief valve 36. After a period of motor operation sufficient to warm the oil and reduce its viscosity, the pressure of the oil which surrounds the plunger 4I at its reduced portion 60 will become sufficiently great to start a forward movement of the plunger 4Il by reaction against a shoulder 62 which terminates the reduced portion 60. This will unseat the face of the plunger from the ,shoulder 6I and admit oil under pressure to exert itself against the area of the plunger in the manner hereinbefore described where it will balance the action of the spring 44 and become effective to control the quantity of oil Iiowing to the pump through its intake passage.

We claim:

1. A motor lubrication system comprising a pump having an intake passage in communication with a reservoir and a discharge passage for directing lubricant to bearing surfaces, a pressure regulated control valve for restricting lubricant flow through the intake passage, and means for communicating regulating pressure to said control valve from the discharge side of the pump.

2. A motorV lubrication system comprising a pump having an intake passage in communication with a reservoir and a discharge passage for directing lubricant to bearing surfaces, a pressure regulated control valve for restricting lubricant ow through the intake passage, and means for communicating regulating pressure to said control valve from the discharge side of the pump and from a point Vadjacent to said bearing surfaces.

3. A motor lubrication system comprising a pump, conduits leading from the discharge side of said pump to bearings to be lubricated, a reservoir for lubricant, a conduit between said reservoir and the intake of said pump, a valve in said intake conduit arranged to restrict the flow of lubricant to the pump, a spring urging said valve to open position, a pressure responsive plunger for closing the valve, and means for directing 6 pressure from said discharge conduits to said plunger whereby the intake capacity of the pump will be regulated by its discharge pressure.

4. In a system for directing lubricant to bear ings or the like, a source of lubricant, a pump having an intake communicating with said source, means communicating the discharge of the pump with the bearings, pressure controlled valve means to `restrict the flow of lubricant to the pump intake, and means to communicate pressure from between the pump and the bearings to the valve means to control the quantity of lubricant being pumped.

GEORGE E. BUR/KS. RONALD R. ROBINSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 822,276 Hodsdon June 5, 1906 1,288,302 Vincent Dec. 1'7, 1918 2,138,969 Hobbs Dec. 6, 1938 2,192,989 Trigg Mar. 12, 1940 l 2,298,646 Ovens Oct. 13, 1942 2,312,063 Allen Feb. 23, 1943 2,443,143 Madsen June 8, 1948 FOREIGN PATENTS Number Country Date 496,536 France Aug. 6, 1919 

